SOC. And so should I. But since this is the case, and we have plenty of time, shall we not quietly, without any impatience, but truly examining ourselves,

 
consider again the nature of these appearances within us? And as we consider them, I shall say, I think, first, that nothing can ever become more or less in size or number, so long as it remains equal to itself. Is it not so? THEAET. Yes. SOC. And secondly, that anything to which nothing is added and from which nothing is subtracted, is neither increased nor diminished, but is always equal. THEAET. Certainly. SOC. And should we not say thirdly, that what was not previously could not afterwards be without becoming and having become? THEAET. Yes, I agree. SOC. These three assumptions contend with one another in our minds when we talk about the dice, or when we say that I, who do not, at my age, either increase in size or diminish, am in the course of a year first larger than you, who are young, and afterwards smaller, when nothing has been taken from my size,
 
but you have grown. For I am, it seems, afterwards what I was not before, and I have not become so; for it is impossible to have become without becoming, and without losing anything of my size I could not become smaller. And there are countless myriads of such contradictions, if we are to accept these that I have mentioned. You follow me, I take it, Theaetetus, for I think you are not new at such things. THEAET. By the gods, Socrates, I am lost in wonder when I think of all these things, and sometimes when I regard them it really makes my head swim. SOC. Theodorus seems to be a pretty good guesser about your nature. For this feeling of wonder shows that you are a philosopher, since wonder is the only beginning of philosophy, and he who said that Iris was the child of Thaumas Hes. Theog. 750 Iris is the messenger of heaven, and Plato interprets the name of her father as Wonder ( θαῦμα ). made a good genealogy. But do you begin to understand why these things are so, according to the doctrine we attribute to Protagoras, or do you not as yet? THEAET. Not yet, I think. SOC. And will you be grateful to me if I help you
 
to search out the hidden truth of the thought of a famous man or, I should say, of famous men? THEAET. Of course I shall be grateful, very grateful. SOC. Look round and see that none of the uninitiated is listening. The uninitiated are those who think nothing is except what they can grasp firmly with their hands, and who deny the existence of actions and generation and all that is invisible.